The relay technology can divide the traditional single-hop link into a plurality of multi-hop links. Since a distance of each hop is shortened, the path loss is reduced. Thus, it helps to improve the transmission quality, to enlarge the communication range, and thereby to provide more rapid and better services for users.
As shown in FIG. 1, in the network where the RN is introduced, the link between the evolved NodeB (eNB) and the Macro User Equipment (M-UE) in the network is called direct link; the link between the eNB and the RN is called backhaul link; and the link between the RN and the Relay User Equipment (R-UE) is called Access Link.
As shown in FIG. 2, in a Long Term Evolution (LTE) system, each radio frame is 10 ms and comprises 10 subframes. One subframe is 1 ms and is divided into two slots; and each slot is 0.5 ms. When the frame structure of the system adopts Normal Cyclic Prefix (Normal CP), each subframe contains 14 Single Carrier-Frequency Division Multiple Access (SC-FDMA) symbols. When the frame structure of the system adopts Extended Cyclic Prefix (Extended CP), each subframe contains 12 SC-FDMA symbols. The uplink physical resource is divided according to the unit of Resource Block (RB). In the time domain one RB is one slot, and in the frequency domain one RB is consecutive NscRB sub-carriers, wherein NscRB=12 or 24.
On the direct link of the LTE system, the uplink physical control information of the M-UE comprises Hybrid Automatic Repeat Request (HARQ) feedback information which comprises ACK/NACK feedback relied on the reception condition of the service data which are sent from the eNB to M-UE, and channel quality report which comprises Channel Quality Indicator/Precoding Matrix Indicator/Rank Indication (CQI/PMI/RI). The CQI/PMI described below indicates CQI and/or PMI. When M-UE needs to transmit both the uplink service data and the UCI on the same subframe, the User Equipment (UE) multiplexes the UCI and the uplink service data according to the configuration, bears the multiplexed UCI and the uplink service data in the allocated Physical Uplink Shared Channel (PUSCH) resource and sends it to the eNB. The eNB allocates the PUSCH resource of the UE according to the unit of RB pair.
In the LTE system, the processing of multiplexing the UCI and the uplink service data and bearing the multiplexed UCI and the uplink service data on the PUSCH is that: respectively coding, multiplexing and interleaving the UCI to be reported, comprising one or more of the ACK/NACK, CQI/PMI and RI information; and finally mapping to the allocated PUSCH resource.
First, it is required to determine the number of coded modulation symbols Q′ according to the relevant configuration and resource allocation of the uplink transmission of the UE configured by the eNB.
For the ACK/NACK or RI information,
      Q    ′    =      min    (                  ⌈                              O            ·                          M              sc                              PUSCH                -                initial                                      ·                          N              symb                              PUSCH                -                initial                                      ·                          β              offset              PUSCH                                                          ∑                              r                =                0                                            C                -                1                                      ⁢                          K              r                                      ⌉            ,              4        ·                  M          sc          PUSCH                      )  
where, O is the number of bits of ACK/NACK or RI control information; MscPUSCH is the number of sub-carriers of the PUSCH resource obtained by the RN for bearing the transmission block (TB) that bears the uplink service data on the current uplink subframe; MscPUSCH-initial is the number of the sub-carriers of the PUSCH resource allocated for the TB that bears the uplink service data of the initial transmission; the number of the SC-FDMA symbols capable of bearing the uplink service data on one subframe in the initial transmission configuration of the TB that bears the uplink service data of the direct link is NsymbPUSCH-initial=(2·(NsymbUL−1)−NSRS); NsymbUL is the number of SC-FDMA symbols on each slot of the uplink; it is 7 when Normal CP is adopted, and is 6 when Extended CP is adopted; NSRS is the number of the SC-FDMA symbol occupied by the Sounding Reference Signal (SRS); C and Kr are relevant parameters for the code block segmentation performed in the uplink service data processing, and specifically, Kr is the number of bits contained in a corresponding code block r in code block segmentation performed for the TB that bears uplink service data; C is the total number of coded blocks after the code block segmentation performed for the TB that bears uplink service data; and βoffsetPUSCH is the offset indication of the UCI modulation coding mode on the direct link; that is to say, when the UCI is borne on the PUSCH, the offset indication determining the number of bits of coded UCI contains 16 values, and the specifically adopted value is configured by a high-layer signalling. For the ACK/NACK information, βoffsetPUSCH=βoffsetHARQ-ACK; and for the RI information, βoffsetPUSCH=βoffsetRI. The parameter tables are as shown in Tables 1-3 below.
TABLE 1βoffsetHARQ-ACK parameter tableIoffsetHARQ-ACKβoffsetHARQ-ACK02.00012.50023.12534.00045.00056.25068.000710.000812.625915.8751020.0001131.0001250.0001380.00014126.00015Reserved
TABLE 2βoffsetRI parameter tableIoffsetRIβoffsetRI01.25011.62522.00032.50043.12554.00065.00076.25088.000910.0001012.6251115.8751220.00013Reserved14Reserved15Reserved
TABLE 3βoffsetCQI parameter tableIoffsetCQIβoffsetCQI0Reserved1Reserved21.12531.25041.37551.62561.75072.00082.25092.500102.875113.125123.500134.000145.000156.250
After Q′ is obtained, according to the configured modulation order, the UE can further determine the number of coded bits of the ACK/NACK or RI, Q=Qm·Q′, wherein Qm is the number of the bits borne by each SC-FDMA symbols in the current modulation order. Specifically, the Qm is respectively 2/4/6 at QPSK/16QA/64QAM.
For the CQI/PMI information,
      Q    ′    =      min    (                  ⌈                                            (                              O                +                L                            )                        ·                          M              sc                              PUSCH                -                initial                                      ·                          N              symb                              PUSCH                -                initial                                      ·                          β              offset              PUSCH                                                          ∑                              r                =                0                                            C                -                1                                      ⁢                          K              r                                      ⌉            ,                                    M            sc            PUSCH                    ·                      N            symb            PUSCH                          -                              Q            RI                                Q            m                                )  
where, O is the number of bits of the CQI/PMI information; L is the number of bits of the CRC contained in the coded CQI/PMI information; βoffsetPUSCH is the offset indication of the UCI modulation coding mode on the direct link; here βoffsetPUSCH=βoffsetCQI; NsymbPUSCH is the SC-FDMA symbols capable of bearing the uplink service data on a subframe of the current transmission configuration of the TB that bears the uplink service data on the direct link; QRI is the number of bits of the coded and modulated RI information on the direct link; and other parameters have the same definitions as above.
The coded bits of UCI information and the uplink service data are further multiplexed and interleaved. The CQI/PMI information and the service data are multiplexed in seise, then interleaved integrally with the ACK/NACK and RI, and finally mapped to the allocated PUSCH resource through processes such as scrambling, modulation and the like, as shown in FIG. 3.
As the RN cannot perform the uplink reception of the Access Link and the uplink transmission of the backhaul link at the same time, the RN may need to arrange certain switch time interval between the Access Link subframe and the Backhaul Link subframe on which the signal switch from reception to transmission or from transmission to reception, so as converse. For the other aspect, in order to avoid interference from the RN uplink transmission to the uplink reception of other RNs, the RN may be configured to reserve some SC-FDMA symbols on the uplink subframe of the Backhaul as interference avoidance protection time. Transmission of uplink signals is not performed on these symbols. The subframe for the backhaul uplink transmission of RN, configured by the system, is called the backhaul uplink subframe. Considering at least one of the above two factors, the number of the symbols which can be practically used for the uplink transmission on the backhaul uplink subframe of the RN may be less than the number of the symbols contained in one subframe. That is to say, when Normal CP is adopted, the usable symbol number may be less than 14; and when Extended CP is adopted, the usable symbol number may be less than 12. As a result, the channel structure of the relay physical uplink shared channel (R-PUSCH) of the backhaul link is different from the PUSCH. Consequently, corresponding process of the direct link cannot be applied to the process of the UCI and the uplink service data of the backhaul link. Otherwise, the system performance may be reduced due to the mapping error.
In addition, in the multiplexing and mapping process of the UCI and the uplink service data of the backhaul link, the eNB needs to indicate the offset indication index of the UCI coding mode for the RN through a signalling with many bits, so the signalling overhead is relatively great.